1. Field of the Invention
The present invention relates to a lens meter capable of measuring refraction characteristics of right and left lenses of eyeglasses with two measurement optical systems, particularly to a lens meter capable of obtaining in a simple manipulation optical characteristics such as a spherical power of a pair of lens attached on a frame of eyeglasses.
2. Description of the Prior Art
Conventionally, a lens meter has been known, which has a configuration that information including a scale drawn in a concentric circle with centering an optical center of eyeglasses; a cross target showing a measurement point of the eyeglass lens; and a measurement value of optical characteristics of the lens being inspected is displayed on a monitor screen of a display, the cross target is moved into a circle in a central area of the scale while looking at the screen, and the optical characteristics (a spherical power S, a cylindrical power C, an axial angle A, prismatic values Px, Py, an additional power ADD) of eyeglass lenses are automatically computed and measured.
In this lens meter, a main switch is turned on to display the concentric scale on the monitor screen and one of a pair of lenses of eyeglasses attached on the frame of eyeglasses is mounted on a lens receiver.
By turning on the main switch, a measurement luminous flux is projected from a measurement projection optical system to the eyeglass lens to be measured, arithmetic measurement is performed to a prismatic quantity at a transmission area of the eyeglass lens where the measurement luminous flux passes, the cross target showing the measurement point of the eyeglass lens is displayed on the monitor screen based on the prismatic quantity, and the eyeglass lens is moved along the lens receiver to make the cross target fall into the scale while looking at the monitor screen.
The optical characteristics of the eyeglass lens are measured in this manner in the conventional lens meter. When the measurement of one eyeglass lens is completed, the optical characteristics of the other eyeglass lens are measured in the same procedure.
Incidentally, the lens meter of this kind has a problem that much time is required for the measurement and the measurement is bothersome because the eyeglass lens must be mounted on the lens receiver again to measure the other eyeglass lens after measuring one eyeglass lens.
Further, although unattended store, manpower reduction and the like are considered in many eyeglasses stores, a visitor himself/herself must operate the lens meter to measure the optical characteristics of lenses of eyeglasses if the lens meter is installed in an unattended store.
However, there exists a problem that the operation of measurement by the visitor in the conventional lens meter is too complicated for the visitor.
The present invention has been created from a viewpoint of the foregoing circumstances. An object of the present invention is to provide a lens meter capable of measuring a pair of lenses of eyeglasses only by playing the eyeglasses on the lens meter with a simple procedure.
To achieve this object, the lens meter of the present invention includes: a unit body provided with an eyeglasses support means for supporting eyeglasses; a left measurement optical system provided in the unit body and provided with a left light-emitting optical system that emits measurement light to a left eyeglass lens of the eyeglasses and a left light-receiving optical system that receives the measurement light passing through the left eyeglass lens with a photo-detecting device; a right measurement optical system provided in the unit body and provided with a right light-emitting optical system that emits measurement light to a right eyeglass lens of the eyeglasses and a right light-receiving optical system that receives the measurement light passing through the right eyeglass lens with the photo-detecting device; and an arithmetic control circuit that performs operation to the optical characteristics of a pair of the eyeglass lenses based on an output of the photo-detecting device.
Further, a pair of the light-receiving optical systems can share one photo-detecting device. The unit body can have: a left lens receiver disposed between the left light-emitting optical system and the left light-receiving optical system and provided with an end portion capable of supporting the left eyeglass lens from underneath with a point; and a right lens receiver disposed between the right light-emitting optical system and the right light-receiving optical system and provided with an end portion capable of supporting the right eyeglass lens from underneath with a point, as the eyeglasses support means. Each of the right and left lens receivers can be formed in a bar shape to be a pair of lens receiving shafts. Upper ends of the lens receiving shafts are formed in a hemispheric shape capable of supporting the eyeglass lens with a point. Further, the unit body can have a pair of pressing members as another lens support means. In this case, a pair of the pressing members severally press each of the right and left eyeglass lenses from above to press the right and left eyeglass lenses severally against the right and left lens receivers.
Furthermore, the unit body can have an elevating support means for eyeglasses as another lens support means. The elevating means for eyeglasses has a configuration that it is attached to the unit body in a freely movable manner up and down and makes the right and left eyeglass lenses of eyeglasses go down until the lenses contact the right and left lens receivers. Further, the elevating support means for eyeglasses may be a nose pad supporting member disposed at a center between the right and left measurement optical systems in a freely movable manner up and down, which is capable of supporting the nose pad of eyeglasses from underneath and positioning the eyeglasses in horizontal directions. The elevating support means for eyeglasses may be a frame-supporting member capable of supporting right and left lens frames of the eyeglasses:
Furthermore, the unit body can have a pair of sandwiching means for eyeglasses, which sandwich the eyeglasses from front and rear directions, as another lens support means. The unit body can have: the nose pad supporting member disposed at a center between the right and left measurement optical systems, which is capable of supporting the nose pad of eyeglasses from underneath and positioning the eyeglasses in horizontal directions; and a pair of the sandwiching means for eyeglasses, which sandwich the eyeglasses from front and rear directions, as another lens support means.
The unit body can have: the nose pad supporting member disposed at a center between the right and left measurement optical systems, which is capable of supporting the nose pad of eyeglasses from underneath and positioning the eyeglasses in horizontal directions; a pair of pressing members that severally press the right and left eyeglass lenses from above to press the right and left eyeglass lenses against the right and left lens receivers; and a pair of the sandwiching means for eyeglasses, which sandwich the eyeglasses from front and rear directions, as another lens support means.
The lens receivers have a configuration that they are provided between a measurement optical path of the measurement optical system and a withdrawal position outside the measurement optical path in a freely movable manner by a lens receiver moving mechanism. A pair of the sandwiching means for eyeglasses, which sandwich the eyeglasses from front and rear directions, are linked or connected with each other so as to move forward or backward by an equal quantity with each other to a measurement optical axis of the measurement optical system.